New engine: Stash

[Terje]

I've only used self-play to validate patches and it seems to work

[mhouppin]

After 18 matches played against each engine (excluding NG-Play that seemed to refuse to boot), the +60 Elo gain seems like a good estimation !

Code: Select all

   # PLAYER                       :  RATING  ERROR  POINTS  PLAYED   (%)  CFS(%)    W    D    L  D(%)
   1 (2176 Elo) Protej 0.5.8c     :  2178.4   25.0    11.5      18    64      67   11    1    6     6
   2 Stash 15.0                   :  2162.4   68.5    49.5      90    55      71   42   15   33    17
   3 (2136 Elo) FoxSEE 3.2.1      :  2139.4   54.7     9.0      18    50      76    7    4    7    22
   4 (2115 Elo) Embla 1.0.3       :  2117.9   25.9    10.0      18    56      86    8    4    6    22
   5 (2102 Elo) BikJump 2.01      :  2101.8   14.7     7.0      18    39      63    5    4    9    22
   6 (2108 Elo) KnockOut 0.7.1    :  2094.8   39.1     3.0      18    17     ---    2    2   14    11

[Ras]

(excluding NG-Play that seemed to refuse to boot)

You could try my bugfix version 9.87b; binaries for Windows are included:
https://www.ct800.net/download/NGplay_9.87b.zip

[mhouppin]

(excluding NG-Play that seemed to refuse to boot)

You could try my bugfix version 9.87b; binaries for Windows are included:
https://www.ct800.net/download/NGplay_9.87b.zip

Thanks, I'll use this version in my tests today ^^

[mhouppin]

Hi there, version 16 is out ! The engine made lots of improvements since last release:

- Pawn structure now scores doubled/isolated pawns;
- King safety has been added to evaluation;
- Static evaluation is now stored in hash entries;
- Null Move Pruning activation has been refined;
- I added History Heuristic for quiet move ordering;
- I increased aggressivity of Late Move Reductions (now depending on depth and move count).

The total should be 100-120 Elo higher than version 15.0.

https://gitlab.com/mhouppin/stash-bot/-/releases/v16.0

[mhouppin]

Hi there, version 17 is out !

This version took more time to get as more and more patches fail to pass, but here are the improvements made:

- Retired King Safety evaluation (loses Elo in regression tests, probably because of the speed loss);
- Improved quiet move ordering on endgames (by using corresponding PST);
- Corrected SEE code (apparently it never worked since version 11, and the correction gave instantly 20 Elo);
- Changed threshold for good captures to -30 cp (B vs N exchanges);
- More UCI-compliant (sending all MultiPV lines at once);
- Little tweaks on time management (allowing partial search results to be used after the alloted time was consumed).

No idea how the rating went, but I would guess Stash is now playing above 2300 Elo.

[mhouppin]

Hi there, version 18 is out !

This update went really fast, but I only did one major patch. I looked back at the King Safety code that I added in version 16 (that failed to improve the engine strength), re-worked slightly on it (by adding pawn attacks to king zone and excluding attacks on squares defended by enemy pawn shelter), and this time the patch passed the regression test with a gain of 86 +/- 38 Elo !

As usual, binaries are available at https://gitlab.com/mhouppin/stash-bot/-/releases/v18.0

Good afternoon to everyone !

[Rebel]

Hi there, version 18 is out !

This update went really fast, but I only did one major patch. I looked back at the King Safety code that I added in version 16 (that failed to improve the engine strength), re-worked slightly on it (by adding pawn attacks to king zone and excluding attacks on squares defended by enemy pawn shelter), and this time the patch passed the regression test with a gain of 86 +/- 38 Elo !

As usual, binaries are available at https://gitlab.com/mhouppin/stash-bot/-/releases/v18.0

Good afternoon to everyone !

Version 18 is doing well.

http://rebel13.nl/srl/Stash.html

[mhouppin]

Hi there, version 19 is out ! New things in this release (compared to version 18):

- Added Delta Pruning to Quiescence Search;
- Added small material specifications to evaluation (Bishop Pair, Rook Pair...);
- Removed PV computations on non-PV nodes;
- Re-indexed search stack so that Killer Moves don't get erased when doing IID search or Null Move Search;
- Added Rook on open/semi-open files, and Rook x-raying Queen to evaluation;
- Changed phase calculation (from piece count to material count).

The new version got a +80 Elo in self-tests, but the gain against other engines should be around 40-50 Elo.

Good evening to everyone !

[MOBMAT]

Hi there, version 19 is out ! New things in this release (compared to version 18):

- Added Delta Pruning to Quiescence Search;
- Added small material specifications to evaluation (Bishop Pair, Rook Pair...);
- Removed PV computations on non-PV nodes;
- Re-indexed search stack so that Killer Moves don't get erased when doing IID search or Null Move Search;
- Added Rook on open/semi-open files, and Rook x-raying Queen to evaluation;
- Changed phase calculation (from piece count to material count).

The new version got a +80 Elo in self-tests, but the gain against other engines should be around 40-50 Elo.

Good evening to everyone !

Previously you had a bmi2 version. is that the same as "modern" now?